Experiments are proposed to elucidate the relationships between gene organization, structure and expression in the nematode, Caenorhabditis elegans. The nematode is used because of its available genetics, small genome and well described cell lineages. The genomic arrangement of the actin and collagen genes is being determined and DNA sequence analysis is in progress. The times of expression of the actin and collagen genes will be determined using the cloned sequences as hybridization probes. Expression will also bae measured by in situ hybridization in specific, well-characterized cell lineages. Experiments will be done to determine if C. elegans actin genes can be expressed and function in yeast in order to assess the conservation of the actin genes. The C. elegans actin and collagen cloned DNA's are being genetically mapped using two interbreeding strains that contain restriction site polymorphisms. More polymorphisms will be sought in other laboratory and wild strans to improve the mapping methds. Some DNA polymorphisms are due to DNA inserts and they will be studied to determine if they are transposable genetic elements. When the actin and collagen genes are mapped, mutants will be used to study the relationship between the genes and the functions of the proteins in the organism.